Various types of antennas are rapidly improvement along with the development of the communication technology. The IC technology is also developed with fast pace to provide a product with smaller size and lighter weight. The volume fact is one of important considerations to the antenna used for transmitting and receiving signal. One goal of the manufacture is to achieve the small product with light weight.
Antenna is employed to transmit or receive EM wave for communication technology. The characters of the antenna can be obtained from the operating frequency, radiation pattern, return loss and antenna Gain. Small size, good performance and low cost are the most important facts for the current antenna to share larger marketing.
I general, the antennas employ a reflector to reflect the EM wave transmitted by the antennas for directing the EM wave towards a pre-determined direction. In order to constrain the EM wave direction, the reflector is configured with a spherical shape or other curved surface, generally. The waves reflected from the above reflector may propagate towards a direction so as to improve the directivity and gains.
However, the well-known reflectors are shaped as spherical shape or parabolic shape or other curved surface. In order to precisely control the focus location of the reflector, it leads to the manufacture procedure is complicated; therefore, the cost is high. Further, it is also unlikely to minimize the size of such reflector.
Further, the conventional reflector is adapted to single one band only, it is impossible to be applied to the wireless transmission standard such as IEEE 802.11a and European HYPERLAN standard (4.9 GHz˜5.9 GHz), IEEE 802.11b (2.4–2.5 GHz). Therefore, the conventional one is not only inconvenient, but also expensive.
Thus, what is desired is to develop a multi-band antenna to meet the requirement of improved reflection effect, easy to manufacture and is adapted to the IEEE 802.11a/b and European HYPERLAN standard.